From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pb0-f49.google.com ([209.85.160.49]) by merlin.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1TYsIQ-0006gv-3G for linux-mtd@lists.infradead.org; Thu, 15 Nov 2012 05:47:27 +0000 Received: by mail-pb0-f49.google.com with SMTP id un15so857849pbc.36 for ; Wed, 14 Nov 2012 21:47:24 -0800 (PST) From: Brian Norris To: David Woodhouse Subject: [PATCH for 3.7] mtd: nand: fix Samsung SLC detection regression Date: Wed, 14 Nov 2012 21:46:30 -0800 Message-Id: <1352958390-15553-1-git-send-email-computersforpeace@gmail.com> Cc: Sylwester Nawrocki , Brian Norris , linux-mtd@lists.infradead.org, Artem Bityutskiy List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , This patch fixes errors seen in identifying old Samsung SLC, due to the following commits: commit e2d3a35ee427aaba99b6c68a56609ce276c51270 mtd: nand: detect Samsung K9GBG08U0A, K9GAG08U0F ID commit e3b88bd604283ef83ae6e8f53622d5b1ffe9d43a mtd: nand: add generic READ ID length calculation functions Some Samsung NAND with "5-byte" ID really appear to have 6-byte IDs, with wraparound like: Samsung K9K8G08U0D ec d3 51 95 58 ec ec d3 Samsung K9F1G08U0C ec f1 00 95 40 ec ec f1 Samsung K9F2G08U0B ec da 10 95 44 00 ec da This bad wraparound makes it hard to reliably detect the difference between Samsung SLC with 5-byte ID and Samsung SLC with 6-byte ID. The fix is to, for now, only use the new Samsung table for MLC. We cannot support the new SLC (K9FAG08U0M) until Samsung gives better ID decode information. Note that this applies in addition to the previous regression fix: commit bc86cf7af2ebda88056538e8edff852ee627f76a mtd: nand: fix Samsung SLC NAND identification regression Together, these patches completely restore the previous detection behavior so that we cannot see any more regressions in Samsung SLC NAND (finger crossed). With luck, I can get a hold of a Samsung representative and stop having to cross my fingers eventually. Reported-by: Sylwester Nawrocki Signed-off-by: Brian Norris --- David: please note that this (and the aforementioned commit bc86cf7a) are urgently in need of a pull request for the 3.7 cycle. I have received several regression reports now, which I have addressed. I would greatly appreciate your attention here! drivers/mtd/nand/nand_base.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c index d5ece6e..1a03b7f 100644 --- a/drivers/mtd/nand/nand_base.c +++ b/drivers/mtd/nand/nand_base.c @@ -2990,6 +2990,7 @@ static void nand_decode_ext_id(struct mtd_info *mtd, struct nand_chip *chip, * ID to decide what to do. */ if (id_len == 6 && id_data[0] == NAND_MFR_SAMSUNG && + (chip->cellinfo & NAND_CI_CELLTYPE_MSK) && id_data[5] != 0x00) { /* Calc pagesize */ mtd->writesize = 2048 << (extid & 0x03); -- 1.8.0